Washing machine appliances can use a variety of fluid additives (in addition to water) to assist with washing and rinsing a load of articles. For example, detergents and/or stain removers may be added during wash and prewash cycles of washing machine appliances. As another example, fabric softeners may be added during rinse cycles of washing machine appliances.
Fluid additives are preferably introduced at an appropriate time during the operation of washing machine appliance and in a proper volume. By way of example, adding laundry detergent and fabric softener simultaneously to liquid water used for a laundry load can negatively affect operation of the washing machine appliance because the two fluid additives can negate each other. Adding insufficient volumes of either the detergent or the fabric softener to the laundry load can also negatively affect washing machine appliance operations by diminishing efficacy of a cleaning operation. Similarly, adding excessive volumes of either the detergent or the fabric softener can also negatively affect washing machine appliance operations by diminishing efficacy of a cleaning operation.
For instance, when too much detergent is added during a wash cycle, detergent can remain in articles after a rinse cycle because the rinse cycle may not be able to remove all of the detergent from the articles. Unremoved detergent can cause graying within such articles as the detergent builds up over time, can contribute to a roughness feeling of such articles, and can trigger skin allergies. The unremoved detergent can also negatively affect the efficacy of fabric softener during the rinse cycle. Further, unremoved detergent can also cause excess suds that can damage the washing machine and/or decrease a spin speed of the washing machine appliance's drum thereby causing articles therein to retain excessive liquids.
As a convenience to the consumer, certain washing machine appliances include systems for automatically dispensing detergent and/or fabric softener. Such systems can store one or more fluid additives in bulk and dispense such fluid additives during operation of the washing machine appliances. However, accurately dispensing a particular volume of fluid additive with such systems can be difficult. For example, hoses or other conduits are typically used to direct fluid additive from a tank to the washing machine appliance's tub. Air within such hoses can negatively affect measurements of fluid additive dispensed by such systems.
Accordingly, a washing machine appliance with features for accurately dispensing a volume of fluid additive would be useful. In particular, a washing machine appliance with features for accurately dispensing a volume of fluid additive despite the presence of air within a dispensing system of the washing machine appliance would be useful.